Fractionated low-dose radiotherapy primes the tumor microenvironment for immunotherapy in a murine mesothelioma model

Bibliographic Details
Title: Fractionated low-dose radiotherapy primes the tumor microenvironment for immunotherapy in a murine mesothelioma model
Authors: Rebecca A. D’Alonzo, Synat Keam, Suki Gill, Pejman Rowshanfarzad, Anna K. Nowak, Martin A. Ebert, Alistair M. Cook
Source: Cancer Immunology, Immunotherapy, Vol 74, Iss 2, Pp 1-16 (2025)
Publisher Information: Springer, 2025.
Publication Year: 2025
Collection: LCC:Neoplasms. Tumors. Oncology. Including cancer and carcinogens
Subject Terms: Tumor microenvironment, Vasculature remodeling, Low-dose radiotherapy, Immunotherapy, Neoplasms. Tumors. Oncology. Including cancer and carcinogens, RC254-282
More Details: Abstract Combination immune checkpoint inhibitors (nivolumab and ipilimumab) are currently a first-line treatment for mesothelioma; however, not all patients respond. The efficacy of treatment is influenced by the tumor microenvironment. Murine mesothelioma tumors were irritated with various radiotherapy doses. Radiotherapy induced vasculature changes were monitored by power Doppler and photoacoustic ultrasound and analyzed via mixed-effects models. Tissue staining was used to investigate the immune cell infiltrate of tumors. The optimal radiotherapy schedule was combined with immune checkpoint inhibitors, and the survival of mice was analyzed. Using low-dose, low-fraction radiotherapy allowed favorable modification of the murine mesothelioma tumor microenvironment. Irradiating tumors with 2 Gy × 5 fractions significantly improved blood flow and reduced hypoxia, consequently increasing the presence of CD8+ and regulatory T cells in the tumor. Understanding the transient nature of these changes is crucial for optimizing the timing of therapeutic delivery. The combination of radiotherapy with dual immunotherapy (anti-PD-1 plus anti-CTLA-4) proved highly curative when administered concurrently. A diminishing rate of cures was noted with an increasing delay between radiotherapy and subsequent immunotherapy. Concurrent low-dose, low-fraction radiotherapy emerges as a translatable approach for improving the efficacy of immune checkpoint inhibitors in patients.
Document Type: article
File Description: electronic resource
Language: English
ISSN: 1432-0851
Relation: https://doaj.org/toc/1432-0851
DOI: 10.1007/s00262-024-03889-x
Access URL: https://doaj.org/article/9c1dbb87c18641c4b9fba5cda25674f4
Accession Number: edsdoj.9c1dbb87c18641c4b9fba5cda25674f4
Database: Directory of Open Access Journals
More Details
ISSN:14320851
DOI:10.1007/s00262-024-03889-x
Published in:Cancer Immunology, Immunotherapy
Language:English